I was trying to find some data about the PDP-11s instruction set, so I could look up the bvc and sxt instructions in this old snippet. After a quick look around google, I stumbled upon a page talking about an emulated PDP-11 on SIMH; and the idea of keying in a program one instruction and one address at a time on toggle switches.

Then I saw this picture referenced, and thought it worth posting for anyone old enough to have programmed when "cards" were integer to the process: